Apple Files A Patent For Scratch Resistant Stainless Steel

Apple has filed another patent, this one is for scratch resistant stainless steel, and the process used in creating it, which could have already been used in the iPhone 4.

The patent application was filed in April, with an earlier patent application filed a year previously to that, and Apple could also use the scratch resistant stainless steel in a range of other products s well as the iPhone 4.

To make the stainless steel scratch resistant, it is put in a high temperature nitrogen-based salt bath for an hour and a half, and this gives the stainless steel a 15-30 microns thick ceramic nitride layer, which makes it more scratch resistant, without changing the look and color of the stainless steel.